The present invention relates to a method of removing a polymer of a semiconductor device and, more particularly, to a method of removing a polymer which is generated during a dry etching of an oxide layer using a CxFy+O.sub.2 plasma for the purpose of forming a contact hole of a semiconductor device.
A conventional method of removing a polymer of a semiconductor device will be explained below with reference to FIGS. 1A to 1D. Referring to FIG. 1A, an oxide layer 2 is formed on a silicon substrate 1, and a photoresist pattern is formed thereon. Referring to FIG. 1B, when oxide layer 2 is dry-etched using a CxFy+O.sub.2 plasma with the use of photoresist pattern 3 as an etch mask, CxFyOz polymer 4 is left after the dry etching. Here, CxFyOz polymer 4 is not left on a portion where oxide layer 2 is exposed because silicon is generated at the portion during the dry etching and thus CxFyOz polymer 4 is volatilized as SixFy and CxOy. However, CxFyOz polymer 4 is left on a portion where only the photoresist pattern is left because silicon is not generated at this portion.
Referring to FIG. 1C, photoresist pattern 3 is removed through a dry etching. Here, it is not possible to remove CxFyOz polymer 4 through an oxidation of it because photoresist pattern 3 is etched at a higher temperature of above 200 C. Accordingly, as shown in FIG. 1D, the polymer is completely removed using a diluted solution containing HF.
As described above, in the conventional method of removing the polymer, the CxFyOz polymer generated during the dry etching of the oxide layer is not completely removed when the photoresist pattern is removed. Accordingly, an additional treatment using the diluted HF solution is required in order to remove the CxFyOz polymer. This increases the time required for fabrication of the semiconductor device and decreases the characteristic of the device and its production yield.